Locking of inputs

HTML gives us all sorts of wonderful freedom when it comes to dynamically enabling/disabling widgets.

Someone from Concord writes:

> Have buttons enable and disable following the pattern we have in NextGen Interactives ([example](http://is.kcptech.com/dg?moreGames=%5B%7B%22name%22:%22Pendulum%22,%22dimensions%22:%7B%22width%22:600,%22height%22:400%7D,%22url%22:%22DataGames/Games/concord/lab.is/embeddable.html#interactives/inquiry-space/pendulum/1-pendulum.json%22%7D%5D)):
  * At first only start is enabled.
  * Once start is pressed, stop and new run become enabled and start is disabled
  * If stop is now pressed there is data available, so analyze data, and new run become enabled and stop is disabled.
  * If analyze data is pressed data is exported and analyze data is disabled.
  * If new run is pressed and user cancels the dialog, no change in which buttons are enabled/disabled (should currently be start/stop disabled and analyze data/new run enabled).
  * If new run is pressed and user completes dialogs, then either they saved data, or discard it, but either way we are back to the original state - only run is enabled.
while the model is running all other parameter controls are disabled (CO2, brightness, albedo, and clouds)

Dan has essentially labeled this as low-priority, saying that we don't have to worry about it at the moment, but explaining that this is a feature that they'd also like (eventually) in Ramp Game, and that it would be nice for both to have it at some point (in the name of consistency).